function getTimer(stringTime) {
    var minute = 1000 * 60;
    var hour = minute * 60;
    var day = hour * 24;
    var week = day * 7;
    var month = day * 30;
    var time1 = new Date().getTime(); //当前的时间戳
    console.log(time1);
    var time2 = Date.parse(new Date(stringTime)); //指定时间的时间戳
    console.log(time2);
    var time = time1 - time2;

    var result = null;
    if (time < 0) {
        alert("设置的时间不能早于当前时间！");
    } else if (time / month >= 1) {
        result = "发布于：" + parseInt(time / month) + "月前";
    } else if (time / week >= 1) {
        result = "发布于：" + parseInt(time / week) + "周前";
    } else if (time / day >= 1) {
        result = "发布于：" + parseInt(time / day) + "天前";
    } else if (time / hour >= 1) {
        result = "发布于：" + parseInt(time / hour) + "小时前";
    } else if (time / minute >= 1) {
        result = "发布于：" + parseInt(time / minute) + "分钟前";
    } else {
        result = "刚刚发布！";
    }
    return result;
}
getTimer("2021-07-02 15:06:36")